Russian President Vladimir Putin attends a communication session with the International Space Station on April 12, 2013.

Russia conducted another successful flight test of its new anti-satellite missile system last month, according to two people with direct knowledge of a classified U.S. intelligence report.

The anti-satellite missile flew for 17 minutes and 1,864 miles before successfully splashing down in its target area.

The latest revelation comes on the heels of the Pentagon's 108-page missile defense review, which marks the first overhaul of America's missile defense doctrine in nearly a decade. The unclassified review, which singles out emerging Russian, Chinese, North Korean and Iranian missile threats, also focuses on anti-satellite capabilities that "could threaten U.S. space-based assets."

According to the missile review, "Russia is developing a diverse suite of anti-satellite capabilities, including ground-launched missiles and directed-energy weapons, and continues to launch 'experimental' satellites that conduct sophisticated on-orbit activities to advance counterspace capabilities."

Russia's PL-19 Nudol, a system U.S. military intelligence assesses will be focused primarily on anti-satellite missions, was successfully tested twice in 2018. The weapon, which was fired from a mobile launcher, was last tested on Dec. 23 and marked the seventh overall test of the system, according to one of the people who spoke on the condition of anonymity.

The Russian anti-satellite weapon is expected to target communication and imagery satellites in low Earth orbit, according to the other person, who also spoke on condition of anonymity. For reference, the International Space Station and the Hubble Space Telescope travel in low Earth orbit.

"I want to tell all those who have fueled the arms race over the last 15 years, sought to win unilateral advantages over Russia, introduced unlawful sanctions aimed to contain our country's development: You have failed to contain Russia," Putin said during a national address in March.

The complicated threats of anti-satellite weapons

A look at the first Lockheed Martin-built GPS III satellite as it is put into the nosecone of a SpaceX Falcon 9 rocket.

A recently unclassified report from the National Air and Space Intelligence Center, or NASIC, explained how the U.S. advantage above the Earth's atmosphere is eroding to "an emergent China and a resurgent Russia."

The NASIC report said there number of foreign intelligence and imaging satellites "has tripled" to 300 in orbit in the last two decades. The U.S. itself has 353 of its own space assets in orbit for those purposes. In response, military superpowers have poured funding into researching and developing anti-satellite weapons.

Missiles are the most high-profile, physical manifestation of anti-satellite weapons. Frank Slazer, the vice president of space systems at the Aerospace Industries Association, told CNBC about how those missiles may be physically effective, but are likely not the "first line of approach on this."

"You'd much rather jam the satellite, blind it [with a laser], or take over its control systems with a cyberattack," Slazer said. "Kinetic impacts could cause problems for other nations, besides the one you are attacking, and possibly for your own system's for many years afterwards."

Both Slazer and the NASIC report pointed to the example of China's anti-satellite test in 2007. China fired an anti-satellite missile at one of its own, discarded weather satellites. The test was successful, but the satellite shattered into thousands of pieces, which continue to zip around in an orbital cloud of deadly debris.

"A huge percentage of the debris in low earth orbit is still attributable to that one test," Slazer said.

As far as the U.S. military's ability to defend against anti-satellite weapons, the assets and capabilities in orbit "are the same as they have been for awhile," Tommy Sanford, director of the Commercial Spaceflight Federation, told CNBC.

Sanford contends that there has not been much in the way of progress when it comes to defending U.S. space-based assets. Sanford gave the example of using networks of smaller and cheaper satellites, like cubesats and nanosats, to offer "effective platforms to augment and support missions carried out by the DoD's larger exquisite satellites."

"The idea behind a distributed architecture for space support is – instead of having one exquisite target – you'd have a system which could presumably survive some loss of its elements and still be able to provide function," Slazer said.

While Sanford said there are concepts which groups like the Defense Advanced Research Projects Agency, or DARPA, are working on, the solutions have yet to mature.

Sanford pointed to NASA's use of small satellites on the recent Mars InSight mission. Two cubesats the size of mailboxes, MarCo-A and MarCo-B, provided critical communications relay capabilities as the InSight spacecraft came in for a landing on the Martian surface.

"The Department of Defense has a game-changing opportunity to build more resiliency into it's space enabled missions by augmenting the larger satellite missions with smaller satellites and commercial services," Sanford said. "The Defense Department knows the value. Now it should follow NASA's lead and implement it."